To provide a differential pressure/pressure detector capable of measuring differential pressure and static pressure concurrently, and a differential pressure transmitter for diagnosing jamming of a connecting pipe using the detector.

A thin-walled part is provided in a silicon chip, strain detecting elements are arranged in the vicinity of the central part and a periphery of the thin-walled part, and the static pressure in a high-pressure side, static pressure in a low-pressure side and the differential pressure therebetween are computed, based on an output from the elements. The jamming in the connecting pipe is diagnosed based on a fluctuation width of computed values. Constitution is simplified and the jamming in the one side connecting pipe is diagnosed, since the elements capable of measuring the differential pressure and static pressure at the same time are used.